It has long been known to house electrical fixtures such as switches and receptacles in an electrical outlet box. The outlet box permits the insertion of electrical wires into the box which are terminated to electrical fixtures. The fixtures then may be mounted to the box which provides protection to the fixtures as well as the wires terminated therein. The outlet box is then mounted to a wall at a convenient location to provide access. Most outlet boxes accommodate one or more electrical fixtures, which terminate standard 110 volt electrical wires.
Outlet boxes are available in a variety of configurations and sizes. The selection of which type of box to use is dependant upon the specifics of the application. The most commonly employed box is a single-gang outlet box, also referred to as a standard outlet box. The single-gang box is ideal for applications in which only one receptacle is required for the application. Standard outlet boxes have opening dimensions of approximately 3″×2-¼″ and are available in a variety of depths. Double-gang and triple-gang boxes are also available, and they typically have the capacity to hold two and three receptacles respectively. A four inch (4″) square box is also commonly employed for multiple receptacle applications.
Typically, outlet boxes are mounted by affixing mounting ears to a wall stud or other structural member. However for some applications, such as exterior uses, the outlet box, may be mounted within a concrete structure. This is accomplished by attaching the box to a form in the desired location. The form is unusually a wooden temporary structure used to contain the poured concrete in the desired shape that is removed after the concrete has hardened. The outlet box remains in the concrete after removal of the form.
It is necessary when using an outlet box in such an application to insure that it is securely affixed to the form to resist being displaced during the concrete pour. Presently, outlet boxes are affixed to the form using nails or screws. Current design boxes usually provide holes on a flange for receiving a fastener such as a nail to affix the box to a form. Upon removal of the forms, the nails (or screws) remain in the concrete, and need to be cut away in order to avoid being in the way during further work such as the installation of drywall. This requires an extra step and can leave an undesirable sharp edge or projection where the fastener was cut.
Therefore it would be desirable to have an outlet box for use in concrete walls, incorporating features which make cutting of the protruding nails or screws unnecessary.